What DocuSign does to protect documents
DocuSign’s security is strong by industry standards. According to its trust pages:
- Documents are encrypted at rest with AES-256 and in transit over HTTPS.
- DocuSign states that its personnel cannot view or access the contents of your agreements. Staff have limited, role-based access to metadata such as envelope history and the subject line.
- Signers don’t need an account, which keeps fewer passwords in circulation.
- Organisations that want to hold their own keys can add DocuSign’s Security Appliance.
For most agreements (an NDA, a vendor contract, an offer letter) that is more than enough.
What “secure” doesn’t mean here
By default DocuSign holds the encryption keys. Its policy says people can’t look at your documents, but its systems can decrypt and process them, which is how it offers features like AI-assisted summaries of an agreement’s key terms. That is a promise about how carefully readable data is handled, not a guarantee that the data is unreadable to the vendor.
The difference shows up in three situations:
- A breach of the vendor. Attackers who reach systems that hold both data and keys can read the data. Against ciphertext without keys, they get nothing.
- Legal process directed at the vendor. A vendor that can decrypt can be compelled to produce readable documents. A vendor without keys can produce only ciphertext.
- Metadata. Envelope subject lines and history are visible to some staff. A subject like “Divorce settlement – J. Smith” says a lot on its own.
When to send sensitive documents another way
Consider an end-to-end encrypted channel when the document:
- contains identity or financial numbers you’d have to report if leaked,
- would harm the client if anyone learned it existed, not just what it says,
- is part of an exchange that continues after the signature (documents, updates, advice).
If you keep using DocuSign for those, keep subject lines generic, avoid putting the sensitive details in the envelope message, and ask whether customer-managed keys are worth it for your firm.
How Brun handles the same step
In Brun, the PDF, the field values, the signature and the signed copy are encrypted in the browser before upload. The keys are in your firm’s browsers and the client’s link, and never on Brun’s servers, so there is nothing for Brun’s systems, staff or an attacker to read, and no AI that could summarise it. Document titles are encrypted too. The tradeoff is real: Brun offers no multi-party routing, templates or integrations, and if your firm loses every key, Brun can’t recover the data.
Full comparison: Brun vs DocuSign.
Sources (checked November 2, 2026): docusign.com/trust/security/esignature, docusign.com/trust/privacy/data-mgmt-privacy, docusign.com/blog/ai-assisted-agreement-summaries-Q-A, docusign.com/products/platform/ai/ai-trust. DocuSign is a trademark of its owner.